The present invention relates to orthotic devices and, in particular, it concerns an orthotic system that operates in either a rehabilitative mode or an assistive mode.
It is known in the field of rehabilitative medicine that providing range of motion to partially and/or fully non-functional limbs prevents muscle atrophy. Range of motion exercises after surgery are known to decrease post-operative pain and swelling.
Historically, movement of the limb was provided “hands on” by a therapist. In recent years, however, the hands of the therapists are being replaced by rehabilitative orthotic devices, the most popular currently appears to be the group on devices referred to as “continuous passive motion” (CPM) machines. While the CPMs relieve the therapist from the mundane job of moving a limb repeatedly through a prescribed range of motion, the machines lack the human hands-on feel of the nuances of how the limb's response to the movement. The lack of sensitivity of the part of CPM machines also creates a situation wherein the limb may be even further damaged by the continuation of movement if an emergency, such as resistance to the movement, occurs. The challenge has become finding ways for machines to collect and implement data with similar results to the “hands-on” data collected implemented mentally by a therapist.
A number of CPM devices have been developed that use resistance to the movement of the device to trigger a modification of the devices movement. These modifications, however, are based only attaining a preset threshold of resistance to movement, and are generally stopping or reversing direction of the actuating member of the device, or a combination of the two. U.S. Pat. No. 4,558,692 to Greiner describes a device that includes an override switch that, if resistance is encountered, will automatically stop and reverse the motor to prevent injury or discomfort to the patient. The Optiflex®, marketed by Chattanooga Group, Inc., utilizes a similar safety feature.
Another attempt to humanize CPM devices is disclosed in U.S. Pat. No. 6,267,735 to Blanchard et al. The Blanchard et al. device is a continuous passive motion device that may be programmed to stop and reverse the direction of its carriage when a patient activates a “Comfort Zone” feature upon experiencing discomfort (luring flexion or extension. The device may be programmed to establish a reduced range of motion or Comfort Zone for a number of cycles of flexion and extension, after which the range of motion will preferably be gradually and automatically increased or advanced until flexion and/or extension may be carried out at the point at Which discomfort was experienced. The preferred embodiment of the Blanchard et al. device thus provides the patient with immediate relief from discomfort while allowing flexion and extension to continue automatically and in a controlled manner until flexion and/or extension may be carried out at the point at which discomfort was experienced. In this way, the preferred embodiment of the Blanchard et al. device provides a CPM device which may be operated so as to decrease the likelihood that the patient will experience similar discomfort when the carriage returns to the point along the axis of the frame at which discomfort was initially experienced (and at which the Comfort Zone feature was actuated). The human element, however, is just that, and while the Blanchard et al. device allows a wider range of human input to the operational parameters of the machine, it does not provide information relating to the bodies response to therapy other than discomfort zones.
The above referenced CPM machines are characterized as being for therapeutic rehabilitation use. The Motorized Upper Limb Orthotic System (MULOS) developed by the Centre for Rehabilitation and Engineering Studies (CREST), University of Newcastle upon Tyne, UK, is a device that can operate in a CPM mode or an assistive mode. In its assistive mode, the device is controlled by a joystick so as to direct the movement of the limb. The MULOS is also a very large device that is mounted on a wheelchair.
Another field of art pertinent to the present invention is that of isokinetic systems, such as those disclosed in U.S. Pat. No. 4,711,450 to McArthur, U.S. Pat. No. 4,885,939 to Martin, and U.S. Pat. No. 4,601,468 to Bond et al. These devices are generally large, non-portable, single function machines, and must be operated by trained professionals. Some of the devices in this category are able to adjust the level of resistance to movement as either more resistance or less resistance, however, their use is limited to diagnostic measurement of a single joint, and a different device is used for actual therapy sessions.
Other than emergency stop procedures, the data collection of the above referenced devices is limited to collection of data for use in subsequent therapeutic sessions. None of these devices is configured to collect data in real time for substantially immediate implementation.
There is therefore a need for a portable orthotic system that collects data regarding limb movement, (displays representations of the data in real time, and modifies current device function based upon such data so as to meet predefined therapeutic treatment parameters with regard to device-actuated movement needs of the limb regarding device-actuated movement, and/or assist limb rotation. It would be of benefit if the system could be operated by a patient, at least during therapy sessions and when used as an assistive device. It would be of further benefit if the system could be used outside of a clinic, such as in a patient's home, with data communication to a clinic.